Method of forming a raised metal character on a vitreous surface



Unite States Patent METHGD 0F FORMWG A RAISED METAL CHARACTER ON A VITREOUS SURFACE Constantine Velonis, Forest Hills, and William 'Karp, New York, NIX, assignors to 'Grap'hire Corporation, New York, N. Y., a corporation of New York No Drawing. Application March 22, 1951,

' Serial No. 217,057

'5 Claims. (Cl. 117-38) This invention relates to methods of printing and decorating (by spraying and otherwise) glass and other vitreous surfaces with gold and other precious metals with the purpose of having said decorations appear to be in relief of the precious metals. This application is a 'continuation-in-part of application Ser. No.' 100,098, filed by us on June 18, 1949, now abandoned.

In the past it has been customary in the industry to print a prepared formula of gold upon glass bottles, drinking glasses or other vitreous surfaces by means of a screen process and fire it on. However, all of these commercially available precious metal formulae are compounded so that the gold or other metal is assoc1ated with a heat dispersible binder whereby the only sol1d remaining after firing is the precious metal itself. The thickness of the decoration or lettering resulting from this conventional process is extremely small. When gold is the precious metal used the resulting layer averages approximately .000004 to .00001 inch in thickness. Naturally, this gives the appearance of the gold lylng absolutely fiat with the glass.

When using precious metal for this type of work, it is desirable to have the design give a raised or embossed effect which enhances its visual appearance. Gold lying flat or absolutely co-planar with a vitreous surface loses the effect of its beauty unless viewed along a line perpendicular to the surface due to the absence of appropriate reflecting surfaces. On the other hand, should the design or lettering be actually raised then the light rays are so reflected as to show off the gold from any position. Furthermore, the massive effect of precious metal applied in relief to such articles as drinking glasses, art pieces, etc. is extremely desirable and impressive. A formula with sufficient precious metal-cooperating with it to give the result of a relief or embossed effect has r never been compounded commercially as the cost of such a composition due to the market value of such precious metals as gold would 'be exorbitant and certainly not commercially feasible to the glass industry.

An object of this invention is to provide a method of printing or decorating (by spraying or otherwise) whereby it would be commercially practical 'to print or decorate a .design having a raised or embossed or dimensional e'tfect without the expense .thereof being prohibitive.

In order to carry out our invention we first .print the desired design through a stencil screen upon the glass or other surface using a material composed of glass, flux or frit which is suspended in a volatile binder such as what is known in the industry "as squeegee oil. This material is available commercially and well known to the trade.

By way .of clarification it is pointed .out that in :rela- .tion to ceramic decorating, flux means a prepared, .low melting, powdered glass, usually colorless, which may be mixed with pigments to produce, :upon firing, vitrifiable coatings on glass or clay 'ware. Most common fluxes contain large percentages of lead oxide and fuse .attemperatures below 1200 F. The following is a typical formula for flux used with vitrifiable pigments, applied on glassware:

Boric oxide r 2,701,214 Patented Feb. 1, 1955 This flux when used in our process is used without pigments and is clear and transparent when matured to the proper temperature. If the flux is pigmented, this will not affect the final result, except to give different color through the back of the glass. The purpose of this flux is to give an underbody for the gold to follow. The above fiux formula will mature at about 950 F.

Maturation as used in the ceramic industry is the point of temperature at which a ceramic coating begins to fuse itself together and onto the base to which it has been applied. v A ceramic coating such as the flux that is used in this process, is in its original and useable state, a powdery substance which has been suspended in a combustible resinous vehicle. When this material is applied to a ceramic body :and then heated, the resinous vehicle will have fired away before the coating has reached its maturation point. As the coating reaches its maturation point the elements in the coating begin to soften and upon reaching maturation it will have polymerized into a continuous and glossy film and fuse itself to the ware to which it was applied. If fired beyond the maturation point, the coating will begin to flow and drip on the ware.

The flux previously illustrated is chosen because it is suitable for use .on soft glass, and will fuse onto the glass before the glass begins to deform. It also has the characteristic of maturing to a very 'high gloss. Other fluxes may be used for harder glasses or for different ceramic bodies; .the rule being to be certain that the maturing point of the flux is below that of' the softening point of the glass or other bodies to be decorated.

in addition, the glass flux must have an expansion and contraction coefficient, closely matching that of the base glass, or ceramic body, and have a low fusing point to permit development of a good gloss at a permissible temperature. The ultimate requirement for the flux is to achieve an image of the decoration in a very high gloss, and give an appearance of embossed relief.

Another formula for a flux may be as follows, although variations may be made so that maturation can be achieved at different temperatures, and to adjust for coefiiciency of expansion and contraction to the body to be decorated:

Percent Lead oxide 50 Boric oxide 10.8 Silica 35.2 Soda 4 The desired result is obtained due to the fact that the flux composition contains inexpensive solids that do not .fire away, and, also, .to the fact that a screen stencil will permit a sufficient deposit of this material to achieve a raised efiect. Additional relief may be obtained by dusting the wet print with a dry powder of the same or similar material which has been sifted through approximately to 200 mesh. 'The dusting, of course, will be done while the screen print is still wet and tacky and before firing. However, suificient relief may .be obtained with the screen print alone, the amount of relief being dependent upon .the thickness :of .the stencil or screen. However, since the thickness of an eflicient screen is limited, where .a very high relief is desired the dusting process is useful.

The body bearing the flux image is then .fired to the maturing point of the :flux. It is then possible to print by .the screen process over the relief image with the prepared precious metal formula .such as bright gold. The gold paste .or squeegee :gold used in this process is a prepared formula sold commercially by various manufacturers. 'Itisessentiallyan organic gold compound ona ceramic .glaze, or on glass, and heated .to maturity,

it yields, without further treatment, a highly specular gold film reflecting light like a mirror.

The thickness of the fired gold film is extremely small as previously mentioned. .Such .a .thin film may volatilize at .high temperatures, and .in order to make it =fire- :resistant, :a .small amountof rhodium resinate is incorporated in the gold. Essentially the gold consists of the following material:

. Gold (about 11%) Volatile oils Solvents Resins Rhodium resinate Metal organic fluxes The same screen may be used for the gold printing step, or, if desired, another one that is made in exact register with the one used for the flux. The metallic print is then fired to a point slightly below the maturing point of the flux that is used. This is important since, otherwise, the flux or frit, if fired too high, will absorb or craze the metal that was applied. While the gold or other metallic compound may be applied by the normal screen method, it is also possible to apply gold or other precious metals by spraying the same over the flux printed body and firing at or below the maturation point of the flux. give the appearance of the decoration being in metallic relief while the rest of the background remains in metallic.

A typical application of this process on a drinking tumbler, for example, would be as follows:

A sill; screen stencil is prepared of a design to be printed on a tumbler made of glass having a softening point somewhere around ll50 F. This stencil may be prepared in any conventional manner. The use of silk, steel, nylon or any other type of suitable mesh is strictly a matter of choice. In this case steel would be preferable material for the screen since steel has a tendency to deposit a more substantial amount of flux on the Ware. The design is then printed on the ware with a prepared flux composed of 80% lead oxide, silicon dioxide and 10% boric acid which has been dispersed in a vehicle of squeegee oil. Squeegee oil is a temporary printing medium for the flux. It is completely combustible and will fire away completely before the flux reaches its maturation point. The flux chosen in this case is one that will mature at approximately 950 F. The ware is then fired to this temperature and then allowed to cool. A print or decoration in embossed relief is therefore achieved.

The same screen or another one which is in exact register to the first, is then used for the printing of the gold. The gold is printed in register and on top of the image of flux. The ware is then fired to a temperature of about below the maturation point of the flux. if it is fired any higher the movement of the fiux at its maturing point would engulf and absorb the very thin film of gold which has formed itself at the surface of the flux. After cooling, the ware is then complete and the design imprinted thereon will appear to be in gold relief.

We also find that we can spray gold onto opalware with good results. Heretofore, it has been impossible to secure a good gold coverage on opalware by directly spraying or printing on it due to the fact that the opal. gives oif fluorides that destroy the appearance of the gold, but in our method we first spray the opalware with a flux or frit and fire to the maturation point of such fiux or frit. We then spray with gold and fire below the maturation point of the flux or frit.

The result of the use of all our processes above described is a gold decoration or letter which gives the effect of having considerable thickness and dimension which gives the effect of a heavily embossed gold letter or decoration.

Our process is a process for mechanically producing embossed gold designs on ceramic materials. Our process increases the production per day per person several thousand fold. Also, since machines can be employed, our process results in an inexpensive article having characteristics of appearance normally expected only in articles of great value. This makes it possible for an average household to possess richly gold-encrusted ceramic objects which, up to this time, were considered to be museum pieces only.

It will be appreciated that in describing our invention we have used gold as an example, but our method is equally applicable to printing with other precious materials such as platinum and silver, etc.

We claim:

1. A method of forming on a vitreous surface a precious metal character raised substantially above the plane of the vitreous surface to give the appearance of a glossy solid QM hU-INH This will precious metal character attached to said surface consisting of printing the character through a screen onto the surface with a paste comprising a ceramic flux having a volatile binder, firing the flux at a temperature equal to the maturation point of the flux but below the softening point or" the vitreous surface thus forming a smoothed surfaced character raised substantially above the plane of the vitreous surface, coating the raised characters so formed by printing over the raised portions thereof with a screen having identical printing areas as the first screen and with said. areas in exact register with said raised character with a precious metal composition in colloidal suspension in a heat dispersible binder and firing the metal composition at a temperature below the maturation point of the flux, but of sufficient heat to cause maturation and adhesion of the applied precious metal compound to the previously formed raised character to produce an article having glossy smooth raised characters of coated metal extending above the plane of said surface.

2. A method of forming on a vitreous surface a precious metal design raised substantially above the plane of the vitreous surface to give the appearance of a glossy solid precious metal design attached to and extending above said surface consisting of rinting the design through a screen with a substantial amount of a paste consisting of a vitreous flux having a volatile binder having a lower melting point than the vitreous surface, thus forming a design raised substantially above said surface, firing the design to the melting point of the fiux thus causing the flux to fuse to the surface, thus forming a permanent smooth surfaced design raised substantially above the surface, coating the raised design so formed by printing over the raised design with a screen having identical printing areas as the first mentioned screen with said areas in exact register with the raised design and with a prepared solution of precious metal in a heat dispersible binder then firing the solution to a point just below the maturing point of the flux with sufiicient heat to cause matura tion and adhesion of the applied metal, thus producing an article having a glossy smooth raised design of coated metal extending above the plane of said surface.

3. A method of forming on a vitreous surface, a precious metal character raised substantially above the plane of the vitreous surface to give the appearance of a glossy solid precious metal character attached to said surface consisting of printing the character through a screen onto the surface with a wet paste comprising a ceramic flux having a volatile binder, dusting the character while wet with a dry ceramic flux powder, firing the flux at a temperature equal to the maturation point of the flux but below the softening point of the vitreous surface thus forming a smooth surfaced character raised substantially above the plane of the vitreous surface, coating the raised character so formed by printing over the raised portions thereof with a screen having identical printing areas as the first screen and with said areas in exact register wit said raised character with a precious metal composition in colloidal suspension in a heat dispersible binder and firing the metal composition at a temperature below the maturation point of the flux, but of sufiicient heat to cause maturation and adhesion of the applied precious metal compound to the previously formed raised character to produce an article having a glossy smooth raised character of coated metal extending above the plane of said surface.

4. A method of forming on a vitreous surface a precious metal character raised substantially above the plane of the vitreous surface to give the appearance of a glossy solid precious metal character attached to said surface consisting of printing the character through a screen onto the surface with a wet paste comprising a ceramic flux having a volatile binder, dusting the character while wet with dry ceramic flux powder sifted through approximately a to 200 mesh, firing the flux at a temperature equal to the maturation point of the flux but below the softening point of the vitreous surface thus forming a smooth surfaced character raised substantially above the plane of the vitreous surface, coating the raised character so formed by printing over the raised portions thereof with a screen having identical printing areas as the first screen and with said areas in exact register with said raised character with a precious metal composition in colloidal suspension in a heat dispersible binder and firing the metal composition at a temperature below the maturation point of the flux. but of sufficient heat to cause maturation and adhesion of the applied precious metal compound to the previously formed raised character to produce an article having a glossy smooth raised character of coated metal extending above the plane of said surface.

5. A method of forming on a vitreous surface a gold character raised substantially above the plane of the vitreous surface to give the appearance of a glossy solid gold character attached to said surface consisting of printing the character through a screen into the surface with a paste comprising a ceramic flux having a voltaile binder, firing the flux at a temperature equal to the maturation point of the flux but below the softening point of the vitreous surface, thus forming a smooth surfaced character raised substantially above the plane of the vitreous surface, coating the raised character so formed by printing over the raised portions thereof with a screen having identical printing areas as the first screen and with said areas in exact register with said raised character with a gold composition in colloidal suspension in a heat dispersible binder and firing the gold composition at a temperature below the maturation point of the flux, but of sufiicient heat to cause maturation and adhesion of the applied gold to the previously formed raised character to produce an article having a glossy smooth raised character of gold extending above the plane of said surface.

References Cited in the file of this patent UNITED STATES PATENTS 748,849 Duncan Jan. 5, 1904 1,641,820 Lewis Sept. 6, 1927 1,852,759 Shaw Apr. 5, 1932 1,905,565 Lind Apr. 25, 1933 2,346,579 Henderson Apr. 11, 1944 2,587,152 Harlan Feb. 26, 1952 FOREIGN PATENTS 5,420 Great Britain Apr. 14, 1887 

1. A METHOD OF FORMING ON A VITREOUS SURFACE A PRECIOUS METAL CHARACTER RAISED SUBSTANTIALLY ABOVE THE PLANE OF THE VITREOUS SURFACE TO GIVE THE APPEARANCE OF A GLOSSY SOLID PRECIOUS METAL CHARACTER ATTACHED TO SAID SURFACE CONSISTING OF PRINTING THE CHARACTER THROUGH A SCREEN ONTO THE SURFACE WITH A PASTE COMPRISING A CERAMIC FLUX HAVING A VOLATILE BINDER, FIRING THE FLUX AT A TEMPERATURE EQUAL TO THE MATURATION POINT OF THE FLUX BUT BELOW THE SOFTENING POINT OF THE VITREOUS SURFACE THUS FORMING A SMOOTHED SURFACE CHARACTER RAISED SUBSTANTIALLY ABOVE THE PLANE OF THE VITREOUS SURFACE, COATING THE RAISED CHARACTERS SO FORMED BY PRINTING OVER THE RAISED PORTIONS THEREOF WITH A SCREEN HAVING IDENTICAL PRINTING AREAS AS THE FIRST SCREEN AND WITH SAID AREAS IN EXACT REGISTER WITH SAID RAISED CHARACTER WITH A PRECIOUS METAL COMPOSITION IN COLLOIDAL SUSPENSION IN A HEAT DISPERSIBLE BINDER AND FIRING THE METAL COMPOSITION AT A TEMPERATURE BELOW THE MATURATION POINT OF THE FLUX, BUT OF SUFFICIENT HEAT TO CAUSE MATURATION AND ADHESION OF THE APPLIED PRECIOUS METAL COMPOUND TO THE PREVIOUSLY FORMED RAISED CHARACTER TO PRODUCE AN ARTICLE HAVING GLOSSY SMOOTH RAISED CHARACTERS OF COATED METAL EXTENDING ABOVE THE PLANE OF SAID SURFACE. 